Pressure gauge for inflated bodies



April 28, 1931.- v. A. TRIER' PRESSURE GAUGE FOR INFLATED BODIES Filed Jan. 4. 1929 1m. 722w; W.

teiih kii wfiml I III VI/V Patented Apr. 28, 1931 "1 T A TEE PATENT QFFICE PRESSURE GAUGE FOB .INFL'AIIED BODIES Application filed January 4, 1929, Serial No. 380,258,'and in Great Britain February 15, 1928.

This invention relates to pressure gauges -i0r pneumatic tyres or other elasticarticles v:and in particular to gauges of the kind comprising a casing containing a spring-con- "trolled plunger :havingan abutment adjacent thereto which comes into contact with that portion of'thetyre which is not indented by the plunger when the whole device is pressed against thetyretosecure a reading by means of a pointer or the like.

Pressure gauges of theabove'typ'e as hitherto made are open to the disadvantage that if carelessly used so that abutment is pressed into the tyre after it has made contact therewith, a false reading is obtained and it is the object of this invention to provide a device of the above general type of simple construction which will invariably give a correct reading without any skill on the part of the operator.

According to this invention the device comprises a casing containing a spring-controlled plunger, a movable indicating member actuated by the plunger, an abutment surrounding or adjacent to the plunger and means to prevent further movement of the indicating member when the abutment makes contact with that part of the tyre or other elastic body which is not actually depressed by the plunger. Thus in the event of the wall of the tyre being depressed by contact with the abutment owing to unskilful use of the device, to further movement of the indicator will occur and the correct reading will be given.

The particular way in which the desired result can be obtained will, of course, vary within wide limits in accordance with the construction and design of the pressure gauge and indicating device, but in a convenient arrangement where a pointer operatively connected to the plunger moves over a scale, both the scale and the pivot of the pointer are con nected to the abutment and mounted to slide as a unit so that directly the abutment makes contact with the wall of the tyre further pressure thereon moves the scale and pointer temporarily out of operative connection with the plunger thus preventing any further movement of the pointer. Alternatively a portion of the abutment may project which, on making contact with the tyre, will prevent the moving F on which the pointer -passes freely through a slot B 'B, the lower end of the slot being so positioned that when the plunger B is moved into scale and pointer, or by rotation between those or similar parts.

When, as is usually controlled by one or more adjustable springs, these springs may be employed to return the abutment or the movable portion thereof to its initial position as well as to restore the plunger to its inoperative position after the pressure has been released. I

One construction of gauge according to this invention is illustrated by way of example in the accompanying drawing-s, in which Figure 1 is an elevation,

parts in dotted lines, Figure 2 is a plan, .l igure 3Ais a cross-section on the line 33 of Figure l, and,

Figure 4 is a reverse view of Figure 1 (the cover ,plate being removed) and showing the gauge applied to the wall of a tyre.

Referring to the drawings the gauge coinprises a casing A having shoulders A and containing a plunger B mounted to jmove within the casing A against the action of a coiled spring C the efit'e'ctivestrength of which canbe adjusted by means of a grub screw 1 in the base of the casing A. Surrounding the plunger B is an abutment D mounted in the casing so as to slide relatively thereto within a recess D in tne same direction as the plunger B. The abutment Dis provided with two internally pro ecting arms D to which are secured by means of screws E two plates E one on each side of the casing A. One of the plates E has a scale delineated upon it and the plates support between them a pin G is pivotally mounted so-as to move over the scale. The arms D are each held in alignment within the casing F A bjnieans Of'lQZlf SDIlIl 'S D The in F 1n the PlllllgQl' its outermost or normal position (as shown the case, the plunger is showing some of lUU in Figures 1 and 3) by the coiled springs C, the lower end of the slot 13 engages the pin F and holds the abutment D also in its normal or outermost position. A separate spring to control the abutment D is thus rendered unnecessary.

The pointer G is turned about its pivot F by means of a lever G on the pointer engaged by a projection B on the plunger B so that When the device is pressed up against the tyre, first the plunger 13 is depressed, thereby moving the pointer G over the scale until the plunger has depressed the tyre to such an extent that the abutment D comes into contact with the wall H of the tyre, as shown clearly in Figure 4. Thereupon. it any further pressure is exerted against the device, instead of the abutment D compressing the tyre, this abutment yields and moves relatively to the casing A within the recess D the arms D thus causing the plates E and the pin F which they carry to move relatively to the casing and consequently to move the lever G away from the projection B The lever G is thus disengaged from the projection B and any further pressure on the device merely causes the shoulders A of the frame A to depress the tyre without afiecting the reading on the scale, since the relative position of the plunger and the member D remain unchanged. I

It will be appreciated that various modifications may be introduced in the construction of the device without departing from the invention, and, for example, the scale need not necessarily move with the abutment so long as relative movement between the scale and the pointer is prevented as soon as the abutment makes contact with the wall of the tyre or other hollow body.

Further, although the invention is primarily intended for testing the pressure within tyres of vehicles, it can be used for other similar purposes.

What I claim as my invention and desire to secure'by Letters Patent is 1. In a pressure gauge for inflated bodies, the combination of a casing, a spring-pressed plungerproiecting from said casing and adapted to be pressed against the inflated body, an abutment adjacent to the plunger and mounted to slide within the casing relatively to the plunger, a pivot connected to the abutment, a pointer on said pivot, and means actuated bythe plunger to turn the pointer upon its pivot only until the abutment and pivot slide as a unit with the plunger when the abutment makes contact with that part of the inflated body not actually depressed by the Plunger.

2. In a pressure gauge for inflated bodies, the combination of a casing, a spring-controlled plunger projecting irom said casing and adapted to be pressed against the inflated body, an abutment adjacent to the e Within the a plate bearthe abutmen on the pivot, and an ection between the pointer herebythe point nger and mounted to slid ng relatively to the plunger, ing a scale connected to on the plate, operative conn the plunger w over the scale by the plunger u e and the pivot s er is moved til the abutlide as a unit lunger when the abutment of the inflated the plunger.

ment, the plat relatively to the p makes contact with that part bodynot actually depressed by ure gauge for inflate the combination of a casing jecting from said casi cent to the plunger within the casing re a pivot connects on said pivot, m to turn the pointer the abutment and with the p] ward movement of t tending to restore pointer carried ther 3. In a press a plunger probutment adjaand mounted to slide latively to the plunger, d to the abutment, a pointer s actuated by the plunger upon its pivot only until the pivot slide as aunit a spring resisting inhe plunger and thereby the abutment and the eby to its operative posi- ,unger, and

ve signed my l ANTHONY TRIER. 

